populateRevisionLength.php

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<?php
require_once __DIR__ . '/Maintenance.php';

class PopulateRevisionLength extends LoggedUpdateMaintenance {
    public function __construct() {
        parent::__construct();
        $this->mDescription = "Populates the rev_len field";
        $this->setBatchSize( 200 );
    }

    protected function getUpdateKey() {
        return 'populate rev_len';
    }

    protected function updateSkippedMessage() {
        return 'rev_len column of revision table already populated.';
    }

    public function doDBUpdates() {
        $db = $this->getDB( DB_MASTER );
        if ( !$db->tableExists( 'revision' ) ) {
            $this->error( "revision table does not exist", true );
        } elseif ( !$db->fieldExists( 'revision', 'rev_len', __METHOD__ ) ) {
            $this->output( "rev_len column does not exist\n\n", true );
            return false;
        }

        $this->output( "Populating rev_len column\n" );

        $start = $db->selectField( 'revision', 'MIN(rev_id)', false, __METHOD__ );
        $end = $db->selectField( 'revision', 'MAX(rev_id)', false, __METHOD__ );
        if ( !$start || !$end ) {
            $this->output( "...revision table seems to be empty.\n" );
            return true;
        }

        # Do remaining chunks
        $blockStart = intval( $start );
        $blockEnd = intval( $start ) + $this->mBatchSize - 1;
        $count = 0;
        $missing = 0;
        $fields = Revision::selectFields();
        while ( $blockStart <= $end ) {
            $this->output( "...doing rev_id from $blockStart to $blockEnd\n" );
            $res = $db->select(
                'revision',
                $fields,
                array(
                    "rev_id >= $blockStart",
                    "rev_id <= $blockEnd",
                    "rev_len IS NULL"
                ),
                __METHOD__
            );
            # Go through and update rev_len from these rows.
            foreach ( $res as $row ) {
                $rev = new Revision( $row );
                $content = $rev->getContent();
                if ( !$content ) {
                    # This should not happen, but sometimes does (bug 20757)
                    $this->output( "Content of revision {$row->rev_id} unavailable!\n" );
                    $missing++;
                }
                else {
                    # Update the row...
                    $db->update( 'revision',
                             array( 'rev_len' => $content->getSize() ),
                             array( 'rev_id' => $row->rev_id ),
                             __METHOD__ );
                    $count++;
                }
            }
            $blockStart += $this->mBatchSize;
            $blockEnd += $this->mBatchSize;
            wfWaitForSlaves();
        }

        $this->output( "rev_len population complete ... {$count} rows changed ({$missing} missing)\n" );
        return true;
    }
}

$maintClass = "PopulateRevisionLength";
require_once RUN_MAINTENANCE_IF_MAIN;